The Subaru Impreza WRX STI (formerly STi, officially changed in 2006)[1] is the highest standard-edition trim in the Subaru Impreza compact car line, produced by Japanese automaker Subaru.

In the late 1980s, Subaru created the Subaru Tecnica International (STI) division to coordinate development for the FIA World Rally Championship and other motorsports activities. After the company had grown, the division was used to create high-performance consumer versions of the Subaru Impreza WRX, an all-wheel drive car with a turbocharged flat-4 engine, leading to the development of the Impreza WRX STi. The Subaru World Rally Team has used a race-prepared version of the WRX STI as its rally platform since the model trim's creation.